The present invention relates to tamper-resistant caps for containers and particularly to molded lids and caps for covering the top of aerosol cans that are typically employed to contain paint, lacquer, and other similar materials with a propellant to permit dispensing of the same through a dispensing valve and nozzle after removal of the lid or cap. The present invention is more particularly focused on a cap that is easily attached to a ridge or lip that is present at the top of a necked-in container, but resists removal except with the aid of a simple removal tool such as a screwdriver or other flat bladed instrument.
A typical form of an aerosol can is the so-called xe2x80x9cnecked-inxe2x80x9d can that is usually made of steel and includes a cylindrical body. A dome-shaped shoulder portion is coupled to the top of the cylindrical body to form an annular lip around the top edge of the cylindrical body. The dome-shaped shoulder portion includes a necked-in portion defining a small opening at an upper end that receives a dispensing valve. The dispensing valve is generally coupled to the dome-shaped shoulder portion by a cup shaped metal flange having an outer edge that is secured to the necked-in portion by a rolled over collar that forms a ridge. A spray button is coupled to the dispensing valve to control discharge of pressurized material in the can.
A plastic cap is typically mounted on top of the aerosol can to cover the aerosol spray button of the dispensing valve. To release the pressurized contents of the can in a controlled manner, it is necessary to remove the cap to access the aerosol spray button. Such caps are typically formed in a mold using a plastics material such as polypropylene or high-density polyethylene. The caps are often molded to include a shell conforming generally to the outside diameter of the aerosol can and various internal ribs and flanges adapted to secure the cap to the top of the aerosol can. Molded caps of this general construction can also be used to cover the discharge openings provided in containers other than aerosol cans.
Some plastic caps simply engage an inner or outer edge created around the top edge of the cylindrical body by the annular lip coupling the dome-shaped shoulder portion to the top of the cylindrical body. Such plastic caps are generally easily removed and replaced, even without the use of any tools, thus contributing to possible tampering with, or unauthorized dispensing of, the contents of the aerosol can. Some plastic caps of this type do require a removal tool, such as a screwdriver, be inserted between the lower edge of the cap and the annular lip coupling the dome-shaped shoulder portion to the top of the cylindrical body. Examples of such caps are to be found in U.S. Pat. Nos. 3,334,769 and 3,414,167.
Some other caps include a shell conforming generally to the outside diameter of the aerosol can and an internal structure that engages the ridge presented by the rolled collar junction of the cup shaped metal flange around the dispensing valve and the top of the dome-shaped shoulder portion. Examples of such caps are to be found in U.S. Pat. Nos. 3,633,789; 3,802,607; 3,854,622; 3,807,187; 3,934,751; 4,165,014; 4,303,175; and 5,040,694. While such plastic caps are usually designed to be more difficult for children to remove, the designs do little to deter product tampering and unauthorized dispensing by adults.
Some still more secure plastic caps having the internal structure that engages the ridge presented by the rolled collar junction do require the use of a removal tool, such as a screwdriver, to remove the cap from the aerosol container. Examples of such caps are to be found in U.S. Pat. Nos. 3,532,249; 5,788,107; and 6,112,933. However, a potential hazard is presented by such caps that require use of the removal too in that the act of removal of the cap from the aerosol container can cause damage to, and can even puncture, the dome-shaped shoulder portion of the container.
Despite the enhanced security provided by the caps in the prior art, there is still a need for a one piece cap that requires the use of a removal tool, such as a screwdriver, to disengage the cap from the ridge presented by the rolled collar junction, but requires the removal tool to be inserted and used in a manner that will lessen the likelihood of any damage to the aerosol container.
An aerosol can cap of the present invention is formed by one piece of molded plastic having a top wall with an outside edge. A skirt depends from the outside edge of the top wall to a lower perimeter edge. A plurality of arcuate segments depends from the top wall inside the skirt. Each arcuate segment has an inwardly protruding detent. Each arcuate segment is formed by an inner wall and an outer wall coupled to each other so as to define a space between the walls. An opening is provided in the top wall leading to the space between the walls of an arcuate segment for receiving a removal tool.
The aerosol can cap of the present invention can have a top wall that is substantially planar, but other configurations for the top are also possible such as upwardly domed and cone shaped. The outside edge of the top wall is typically substantially circular and the skirt is typically cylindrical, although other shapes would be possible when desired to conform to or complement the shape of the container to which the cap is to be applied. The lower perimeter edge of the skirt preferably defines a plane so that one seeking to remove the cap from any aerosol can to which the cap has been applied will be discouraged from attempting to insert a removing tool below the skirt lower perimeter edge.
Each arcuate segment preferably includes a bottom wall joining lower ends of the inner wall and outer wall that is of sufficient strength as to successfully resist attempts at puncturing the lower wall by any cap removing tool. The bottom wall joining the lower ends of the inner and outer walls also acts to transfer to the inner wall any force or torque applied to the outer wall by any cap removing tool, which can be used to disengage the inwardly protruding detent on the arcuate segment from any aerosol can to which the cap has been applied. Preferably, the inwardly protruding detent is positioned at a lower end of each arcuate segment inner wall so that outward displacement of any arcuate segment will be sufficient to release the cap from any aerosol can to which the cap has been applied. Each arcuate segment preferably also includes end walls joining the inner wall to the outer wall to contain any cap removing tool within the opening defined by the arcuate segment and inhibit debris from entering between the cap and the top of the aerosol can to which the cap has been applied.
The cap of the present invention is quickly and easily snapped onto the top of an aerosol container. Once in place, the cap of the present invention resists removal except when a removal tool, such as a screwdriver, is inserted substantially vertically downward through an opening in the top wall into one of the plurality of arcuate segments. The removal tool handle is then displaced toward the axis of the aerosol container and cap, which causes an outward movement of the lower end of the arcuate segment in which the removal tool is engaged, thereby releasing the inwardly protruding detent from below the ridge presented by the rolled collar junction between the dispensing valve flange and the dome-shaped shoulder portion of the container. The displacement of the removal tool handle also causes a torque to be applied to the cap that promotes the separation of the cap from the container.
One feature of the present invention is the generally vertically oriented openings in the top wall leading down into the closed end arcuate segments that are intended to receive a removal tool such as a screwdriver. The closed end arcuate segments advantageously restrict the downward movement of the removal tool so that the puncturing or other damage to the top of the aerosol container is significantly inhibited or prevented.
Another feature of the present invention is the positioning of the openings in the top wall leading down into the closed end arcuate segments outward from the axis of the aerosol container. The positioning of the openings advantageously translates the displacement force exerted by the removal tool that moves the inwardly protruding detent from below the rolled collar junction ridge into a torque lifting one side of the cap, thus quickly releasing the cap from engagement with the top of the aerosol container.
Further features and advantages of the invention will become apparent to those skilled in the art from the following discussion of the preferred embodiments as depicted in the accompanying drawings.